Silo.



LEWIS R. ABERCB.O1VIBIE,QI}. ron'rLilnn, OREGON.

S IL 0 Specification of"I;etters ]?atent, Pa,t 1ited Dc. 25, 7.

Application filed April 27, 1916. Serial No. 94,071.

To 1121 whom it may concern:

Be it known that I, LEWIS R. ABERCROMB1E, a citizen of the United States, and a resident of the city of Portland, county of Multnomal1, State of Oregon, have invented a new and useful Improvement in Silos, of which the following is a specification.

My invention relates to silos built of wooden staves. As well known, in order to produce good ensilage, it is necessary to construct an air-tight silo. Since the ensilage process engenders moisture which penetrates into the inner faces of the staves and causes them to swell crosswise, if the bands encircling the staves are not then loosened, there will ensue a crushing strain on the fibers in the abutting edges of the staves, destroying the life of the wood in those parts; and the edges will then tend to rot and crumble away, and in time will no longer form an airtight joint.

To avoid these conditions, the bands of wooden silos must be loosened and tightened with the swelling and contraction of the staves. I discovered that the penetration into the staves of the moisture, due to the ensilage forming process, is not very great, but approximately only a small fraction of an inch, and that the effect of the moisture is greatest at the surface directly exposed thereto, and diminishes proportionately as the distance from such face. This penetration may be imagined as representing a triangle having its base on the interior and its peak located about one eighth of an inch from the inner surface of the stave. Now since the swelling of the stave crosswise will be proportional to the degree of penetration of the moisture, therefore the greatest swelling will be at the inner face of the stave, and will rapidly recede therefrom. Hence, I further discovered that if the abutting faces of the staves are chamfered at the interior, so as to provide a triangular space of a cross area corresponding with said imagined triangle representing the degree of probable penetration of moisture, then the swelling due to the latter is taken care of. In other words, the portions cut away allow for the swelling without having to disturb the tension of the band encircling the silo body,

for the exterior portion of the stave is una represents the staves of the silo. The abutting edges of these staves are so cut as to make the faces 6 lie in a plane radial to the longitudinal axis of the silo. In order to provide for an air-tight joint between the abutting edge faces of the staves, I prefer to make one of said edge faces with a triangular cordance with my invention.

groove 0, and the other with a triangular tongue d, fitting such groove. At the inner faces of the staves, having reference to their position when the silo is put together, one or both of the opposed faces are chamfered, as represented at f, so as to provide a triangular opening between the opposed faces of the staves, for the purpose mentioned.

WVhen the staves are assembled, they are tightly drawn together by encircling bands, not shown, of any convenient type. The moisture developed in the ensilage process will penetrate the inner faces of the staves to a depth approximately corresponding with the peak of the cut-away triangular space 7; and the faces on the opposite sides of this triangular space will be swelled out to such an extent as to come together, but not to such an extent as to tend to force the other abutting edge faces of the staves apart, or exert any crushing strain.

When the ensilage is removed, the air will dry out the inner faces of the staves and so again produce the triangular space f. In this way ample provision is made for the swelling and shrinkage of the stave, due to the moisture developed in the interior of the silo, and the drying out of the latter, and the bands may be tightly drawn up, in the first instance, so as to render the silo air and weather tight, and left in that condition without any further adjustment of the bands being required.

I claim: 1. A silo built of wooden staves, the shut 0 op ies oi this patent may be obtained for ting edge faces of which have at the interior a triangular portion cut away between them whereby the cross-grained swelling. of the slaves clue to the moisture developed within the silo is taken care of.

2. Staves for silos having a portion of one the loof their faces tobe placed-"in abutment with another stave cut away at the interior thereby to provide, when the staves are set up to form a silo, a triangular space, between the edges. of the sta.ves at the interior and accommodate,- the crosswise; swelling of the staves due to the moisture developed within LEWIS R. ABERCROMBIE.

five cents eae11, addressing the Commissioner.,,ot latent, Washington, I). (T. 

